Synera, which is a heated topical patch containing both lidocaine and tetracaine, is intended to reduce the pain associated with venipuncture and superficial dermatologic procedures by numbing the skin. This study will test the effectiveness of the Synera lidocaine/tetracaine patch when administered for 30 ± 5 minutes to provide dermal anesthesia in adult oncology patients undergoing venipuncture as part of their care, for treatment or diagnostics (laboratory or imaging). Compared to the use of the placebo patch, this study hypothesizes that the difference of 1 cm on the 0-10 visual analogue scale (VAS) will be observed 30 minutes after the use of the Synera patch. Pain intensity will be assessed by a 0-10 VAS